Paraproteins and response assessments

Professor Mark Drayson, University of Birmingham 19th March 2015

– what have we learnt from MRC trials?

Paraprotein type at presentation: 2,789 Myeloma 11th trial patients.

Paraprotein type

Number patients

Percent total Kappa : lambda ratio

IgG 

1,665 60

 2.25

IgA

 699

 25

 1.78 

Light Chain

Only

 361

 13

 1.34 

IgD

 35

 1.3

 0.46 

Non Secretor

 23

 0.8

 n/a 

IgM

 6

 0.2

 2.00 

Light Chain Only (6% urine fix negative)serum FLC dif >100mg/l(>500mg/l in 85%)

Non SecretorImmunofixation negative andserum FLC dif <100mg/l(15/23 pts <10mg/l; 5/23pts >50mg/l))

Same findings in Myeloma 9 and inMyeloma 4 - 8

Paraprotein level at presentation:

3

32.7% < 30 g/L 42.3% < 30 g/L

Difficult to monitor paraproteins starting at <10g/l

4

Paraprotein level g/l

IgG

% of 1,665 pts

IgA

% of 699 pts

IgD

% of 35 pts

IgM

% of 6 pts

<5 3.7 6.4 54.2 16.7

5 - <10 4.4 5.7 17.1 0

10 - 20 9.8 14.3 17.1 0

20 - 40 49.0 42.5 11.4 16.7

>40 33.1 31.0 0 66.7

Patients who had a whole paraprotein on serum immunofixation

No difference between kappa andlambda light chain types

FLC enable monitoring of 75% patients with PP <10g/l

5

FLC Level k/ldifferencemg/l

IgG <10g/l

%134pts

IgG >10g/l

%1,531pts

IgA <10g/l

%85pts

IgA >10g/l

%614pts

IgD <10g/l

%25pts

IgD >10g/l

%10pts

<100

 28

 32

 26

 37

 4

 0

100-500

 20

 34

 25

 28

 24

 30

>500

 52

 34

 49

 35

 72

 70

FLC are higher when paraprotein <10g/l (no variation above 10g/l)IgD patients have low paraprotein and high FLC levels – usually lambda

Suppression of polyclonal immunoglobulin

6

ANormal range B

Normal range

C Normal range

n (%) IgG (n =1302)

IgA (n = 2471)

IgM (n = 3228)

Below NR 1049 (80.6) 1981(80.2) 2871 (88.9)

Within NR 253 (19.4) 479 (19.4) 349 (10.8)

Above NR 0 (0.0) 11 (0.4) 8 (0.2)

Median (range) g/L 3.90 (0–15.65) 0.34 (0–5.60) 0.16 (0–3.56)

FLC levels are higher when the light chain type is lambda

7

FLC Level k/ldifferencemg/l

IgG kappa

%1,153pt

IgG lambda

%512pts

IgA kappa

%448pts

IgA lambda

%251pts

LCOkappa

%207pts

LCOlambda

%154pts

<100

 32

 30

 40

 25

 0

 0

100-500

 34

 29

 27

 29

 15

 15

>500

 34

 41

 33

 46

 85

 85

Lambda higher than kappa analysing as continuous variables. Equally nephrotoxic

eGFR by difference between involved and uninvolved FLC (dFLC) clone at presentation in mg/L

8

dFLC <100 dFLC 100-499 dFLC 5000

100

200

300Kruskal Wallis p<0.0001

p<0.0001

p<0.0001p=0.354

median-67 median-66median-52

eG

FR

ml/m

in

Dr Punit Yadav analysis of 1,595 Myeloma 9 patients

Immunoglobulin half lives and response

9

0 20 40 60 80 100 120 140 160 180 20005

1015202530354045

Paraprotein response

IgG paraproteinIgA paraprotein

Days after 100% tumour kill

g/l

0 0.5 1 1.5 2 2.5 3 3.5 40

50010001500200025003000350040004500

Serum FLC response

dFLC

Days after 100% tumour kill

dFLC

mg/

lIgG 21 daysIgA 5 daysFLC 12 hours

Short half lives of serum FLC allowreal time evaluation of tumour kill

10

Paraprotein response to 3 week cycles of myeloma therapy

8 g/l

40 g/l

20 g/l

10 g/l

100

80

60

40

20

1st cycle80% kill

2nd cycle80% kill

3rd cycle80% kill

4 g/l

8g/l

1.6 g/l

4th cycle80% kill (0.16% residue)

IgG

par

apro

tein

g/l

5.0 g/l2.0 g/l

0.8 g/l0.3 g/l

11

FLC response to 3 week cycles of myeloma therapy5000

4000

3000

2000

1000

1st cycle80% kill

2nd cycle80% kill

3rd cycle80% kill

4th cycle80% kill (0.16% residue)

Dif

FLC

mg/

l

4000 mg/l

800 mg/l

160 mg/lnormalise

12

Does a reducing kill rate indicate clonal heterogeneity and predict poor survival?

5000

4000

3000

2000

1000

1st cycle80% kill

2nd cycle20% kill

3rd cycle20% kill

4th cycle0% kill (3.2% residue)

Dif

FLC

mg/

l

4000 mg/l

200 mg/l160 mg/l

normalise

FLC response at end of cycle 1 predicts later response

-40 -20 0 20 40 60 80 100 120

-150

-100

-50

0

50

100

150

Percentage Reduction in FLC at 100 days Post High Dose Melphalan

Perc

enta

ge R

educ

tion

in F

LC a

t th

e En

d of

Cyc

le O

ne

Correlation coefficient=0.155

-60 -40 -20 0 20 40 60 80 100 120

-150

-100

-50

0

50

100

150

Percentage Reduction in FLC Level at the End of Induction

Perc

enta

ge R

educ

tion

in F

LC

Leve

l at t

he E

nd o

f Cyc

le O

ne

Correlation coefficient=0.588

227 Myeloma 11 patients withIgG and IgA paraproteins >10g/land dFLC >100mg/l

Early response in myeloma 11 and the importance of Ig half life

14

-30.0 -10.0 10.0 30.0 50.0 70.0 90.0 110.0

IgG paraprotein (FLC diff <100)

IgG paraprotein (FLC diff >100)

IgG FLC (FLC diff >100)

IgA paraprotein (FLC diff <100)

IgA paraprotein (FLC diff >100)

IgA FLC (FLC diff >100)

All IgG paraprotein

All IgA paraprotein

FLC only

INT/NON-INT COMBINED  Unpaired T-test

(N)

531

117

211

211

756

328

58

531

225

% Reduction in paraprotein/FLC post -cycle 1 - three weeks

 p=0.99

 p=0.07

 p= 5.1E-15

 p= 0.005

 p= 1.4E-07

FLC

FLC

FLC

IgA

IgG

IgG level does not appear to affect IgG half-life in myeloma 11. (FcR neonatal receptor saturated at about 30g/l)

15

IgG

IgA

IgG

IgG

FLC

FLC

FLC

FLC

FLC

No difference in early paraprotein and FLC responses between Intensive and Non-intensive patients 11th trial

16

FLC O

nly RC

D/CTD F

LC Response (n=

160)

FLC O

nly RC

Da/CTDa FLC Response (n=

77)

IgA RC

D/CTD F

LC Response (n=

146)

IgA RC

Da/CTDa FLC Response (n=

114)

IgG RC

D/CTD F

LC Response (n=

360)

IgG RC

Da/CTDa FLC Response (n=

312)

IgA RC

D/CTD P

araprotein

 Response (n=

146)

IgA RC

Da/CTDa Para

protein

 Response (n=

114)

IgG RC

D/CTD P

araprotein

 Response (n=

360)

IgG RC

Da/CTDa Para

protein

 Response (n=

312)

0102030405060708090

100

Perc

enta

ge R

educ

tion

in F

LC/P

arap

rote

in a

t th

e En

d of

Cyc

le O

ne

Figure 1: Percentage reduction in paraprotein and sFLC light chain levels  for patients treated in the MRC Myeloma XI trial at the end of the first cycle of induction chemotherapy.  Whisker boxplots showing the median, 25th and 75th centiles.  Tails represent the 5th and 95th centiles.  The diamonds represent the means.  Mann Whitney U tests were performed to assess the statistical significance of the differences between the groups. RCD=lenalidomide, cyclophosphamide and dexamethasone (320mg/cycle); CTD=cyclophosphamide, thalidomide and dexamethasone (320mg/cycle); RCDa=lenalidomide, cyclophosphamide and dexamethasone (160mg/cycle) and CTDa=cyclophosphamide, thalidomide and dexamethasone (160mg/cycle).

p=0.11 p=0.30 p=0.38 p=0.40 p=0.24

No difference in maximum responses to induction therapybetween Intensive and Non-intensive patients 9th & 11th trial

17

CTD F

LC (n=206)

CTDa FLC (n=143)

RCD/CTD F

LC (n=451)

RCDa/CTDa FLC (n=307)

CTD P

araprotein

 (n=162)

CTDa Parap

rotein (n=110)

RCD/CTD P

araprotein

 (n=346)

RCDa/CTDa Para

protein

 (n=265)

20

30

40

50

60

70

80

90

100

Perc

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tion

in F

LC/P

arap

rote

in a

t th

e En

d of

Indu

ction

p=0.07 p=0.77 p=0.70p=0.13

Figure 2: Percentage reduction in paraprotein and sFLC light chain levels  for patients treated with CTD or CTDa in the MRC Myeloma IX trial and RCD/CTD or RCDa/CTDA in the MRC Myeloma XI trial  at the end of induction chemotherapy.  Whisker boxplots showing the median, 25th and 75th centiles.  Tails represent the 10th and 95th centiles.  The diamonds represent the means.  Mann Whitney U tests were performed to assess the statistical significance of the differences between the groups. RCD=lenalidomide, cyclophosphamide and dexamethasone (320mg/cycle); CTD=cyclophosphamide, thalidomide and dexamethasone (320mg/cycle); RCDa=lenalidomide, cyclophosphamide and dexamethasone (160mg/cycle) and CTDa=cyclophosphamide, thalidomide and dexamethasone (160mg/cycle).

FLC Response Paraprotein Response

IgA45

IgG117

IgA45

IgG117

LCO44

Response at end of induction versus 100d post HDMHDM deepens response but that is not completely evident by 100 d for IgG paras

18

25

35

45

55

65

75

85

95

105

Perc

enta

ge R

educ

tion

in F

LC/P

arap

rote

in

Percentage reduction in sFLC and paraprotein levels  at the end of induction chemotherapy compared toat 100 days post high dose melphalan for patients treated in the MRC Myeloma IX trial.Whisker boxplots showing the median, 25th and 75th centiles.  Tails represent the 10th and 95th centiles. The diamond represents the mean. Mann Whitney U tests p<0.01 for all pairs

FLC Response Paraprotein Response

IgA97

IgG249

IgA97

IgG249

LCO105

19

25

35

45

55

65

75

85

95

105

Perc

enta

ge R

educ

tion

in F

LC/P

arap

rote

in

Percentage reduction in sFLC and paraprotein levels  at the end of induction chemotherapy compared toat 100 days post high dose melphalan for patients treated in the MRC Myeloma XI trial.Whisker boxplots showing the median, 25th and 75th centiles.  Tails represent the 10th and 95th centiles. The diamond represents the mean. Mann Whitney U tests p<0.01 for all pairs

Response at end of induction versus 100d post HDMHDM deepens response but that is not completely evident by 100 d for IgG paras

Serum free immunoglobulin light chain evaluation as a marker of impact from intraclonal heterogeneity on myeloma outcomeBlood 123(22):3414-3419

20

The first 520 patients in myeloma 9 who had an IgA or IgG paraprotein at presentation

At relapse there were three types of relapse:-

1. 183/520 (35.2%) patients had a significant increase in both paraprotein and FLC levels

2. 258/520 (49.6%) patients only had a significant increase in their paraprotein levels       Paraprotein only relapse

3.    54/520 (10.4%) patients relapsed with only an increase in their FLC levels:       Free light chain escape

•24/369 (6.5%) IgG and 30/151 (19.9%) IgA patients relapsed with FLC escape

Effect of Relapse Type on Survival

21

Model of Darwinian Evolution in Multiple Myeloma

22

Is this type of clonal heterogeneity present in response?

23

-80

-60

-40

-20

0

20

40

60

80

100

120

FLCParaprotein

Perc

enta

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educ

tion

in F

LC/P

arap

rote

in

at th

e En

d of

Cyc

le O

ne

IgG and FLC>100mg/l Post cycle one results

-300

-250

-200

-150

-100

-50

0

50

100

150

FLCIgA

Perc

enta

ge re

ducti

on in

FLC

/IgA

at t

he E

nd

of C

ycle

One

IgA and FLC>100mg/l Post cycle one results

Key findingsIgG 60%; IgA 25%; LCO 13%; IgD 1.3%; NS 0.8% (LCO missed in older pts?)

In 10% of patients whole paraprotein <10g/l but can be monitored by FLC

Polyclonal Igs are below normal level in 80% and above normal level in <0.4% (3,228pts)

FLC levels are higher when type is lambda but kappa and lambda FLC are equally likely to be nephrotoxic at the same level. Many patients have non-toxic FLC. FLC levels need to be >500mg/l to have nephrotoxicity.

Ig half life is important when assessing response IgG 21days (7-10d on dex); IgA 5 days FLC <12 hrs

Early FLC response indicates kill rate and can predict max response.

Changing kill rate with subsequent cycles of therapy may indicate clonal heterogenity and poor prognosis

No difference in speed of response or final depth of response between patients on 20 and on 40 mg dex

Light chain escape in 6% IgG and 20% IgA patients. Different relapse patterns indicate clonal heterogeneity.

Patients relapsing with FLC survive worse from relapse than paraprotein only relapses

Some patients have asynchronous FLC and paraprotein response which might also indicate clonal heterogeneity and poor survival

24